Is there a way to edit posts with the API without notifying the user?

Thanks, that seems to work in the UI. I’ll try it with the API tomorrow.

In case anyone else is looking for it in the future:

PUT https://forum.example.com/topics/bulk

Form data copied from the browser console:

topic_ids%5B%5D=12345&operation%5Btype%5D=append_tags&operation%5Btags%5D%5B%5D=tagname

Decoded:

topic_ids[]=12345&operation[type]=append_tags&operation[tags][]=tagname

Update: it worked with the API too.